GB2255135A

GB2255135A - Pressurised fluid operated rotary drive unit.

Info

Publication number: GB2255135A
Application number: GB9208081A
Authority: GB
Inventors: Joerg Niederstadt; Ralf Huber
Original assignee: Mannesmann AG
Current assignee: Vodafone GmbH
Priority date: 1991-04-03
Filing date: 1992-04-03
Publication date: 1992-10-28
Anticipated expiration: 2012-04-03
Also published as: ITMI920809A1; FR2674912B1; GB2255135B; IT1258259B; US5219393A; DE4111116C2; GB9208081D0; JPH05149101A; DE4111116A1; ITMI920809A0; FR2674912A1

Abstract

A housing which can be connected to a source of pressurised fluid is sealed by flat covers 4 and a rotatable shaft 3 extends out of the housing through the covers. A belt 15 is arranged at least partly within the housing, forming movable pressure chambers, and is operatively connected to the shaft 3. To provide a rotary drive unit allowing for extension to external assemblies and modular extension to a plurality of rotary drive units axially extending ducts 2, 2' for conveying the pressurised fluid to the pressure chambers and receiving electric leads are arranged in an integrated manner within the shaft 3 which is provided at its axial ends with coupling elements (20, 21, Fig 2) for coupling mechanical and/or electric additional modules to be driven by the unit. <IMAGE>

Description

0 2255135 Pressure-medium operated rotary drive unit The invention relates

to a pressure-medium operated rotary drive unit, consisting of a housing which can be connected to a pressure medium source, a rotatable shaf t and a belt arranged at least partly within the housing, f orming movable pressure chambers, and operatively connected to the shaft.

A pressure-medium operated rotary drive unit of the type specified is known from US-4 838 148. In this known rotary drive unit, a flexible belt is arranged within a housing having a cavity and forms movable pressure chambers within the housing. These movable pressure chambers are formed by the arrangement of rollers or cylindrical bodies within the housing, by means of which the belt is giided, forming at least one open loop.

The belt is movable in the 'cavity' in such a manner that it varies the open region of the.lobp,,i.e. the region forming the pressure chambers, by means of rolling. This variation is ultimately effected by the pressure mediud-fed into the movable pressure chambers. The belt is situated with its two outer edges lying in 'the housing or in the cavity in such a manner that, firstly, it is still readily movable and, secondly, it provides a pressure-medi umproof seal. The variation or movement of the belt ef f ected by the application of pressure, and with the formation of the abovementioned open loop, causes a detectable rotational movement upon rolling by means of the rotatable roller arranged within the housing. This rotational movement is directed towards the exterior by means of a shaft. one disadvantage of this known embodiment is that external extension to mechanical or nechano-electrical assemblies cannot be effected in the desired manner. The problem with external extension consists not only of the mechanical coupling, but also in effecting electrical and pressure-medium connections from one component or module to the next.

Therefore, the object of the invention, departing from this prior art, is to provide a rotary drive unit allowing for any desired extension via its shaft to external assemblies and modular extension to a plurality of rotary drive units. To this end, according to this invention axially extending ducts for receiving and advancing the pressure medium to the pressure chambers, and electric leads, are arranged within the shaft, the shaft being provided at its two axial ends with coupling elements for the coupling external to the housing of mechanical and/or electric additional modules that can be coupled to the rotational movement.

The advantages of the pressure-medium operated rotary drive unit proposed according,-to the invention-, result from the advantageous coordination of-differ6rit features, which, taken together, allow for simple-modular extension of the rotary drive unit to external a ssemblies or modules. The integrated conveyance in this case of the pressure medium and the electric leads has proven to be particularly advantageous. The integration of the pressure-medium ducts into the shaft of the rotary drive unit and the integration of -the control and servo valves in'to one of the covers results in a compact design. In order then to connect the ducts carrying the pressure medium arranged in an integrated manner in the shaft in a suitable manner to the control valves and to the pressure-medium ports leading towards the exterior, the shaft is provided at least in one of the cover regions with bores protruding radially from the shaft and connected in a gastight manner to the ducts carrying the pressure medium. In order then to connect these bores also in a gastight manner to the control valves or pressure-medium ports, circular grooves are provided on the shaft and are connected in a gastight manner to the ducts carrying the pressure medium. These grooves are for their part connected in a gastight manner by means of integrated ducts to the control valves and to pressure-medium ports leading towards the exterior. In order to obtain suitable tightness, the shaft is further provided with a plurality of annular recesses offset axially with respect to the grooves, in which sealing rings are arranged for sealing the grooves. Therefore, in this arrangement, in spite of the rotational movement of the shaft, an appropriately tight - pressure- mediumproof connection is effected in a particularly advantageous manner between the fixed cover and the ports and control valves integrated therein, and the rotatable shaft containing the ducts.

The servo valves integrated - into - the cover serve in a simple and compact manner to - apply pressure medium to the pressure chambers formed within the housing by the belt.

A plurality of rotary dr ive units can. be.coupled together in order to obtain a high torque that can be detected f rom the outside. In th.is c. onnec tion, once again, the embodiments according to the invention have proven to be extremely advantageous, in that. the ducts carrying the pressure medium and electric leads are arranged i i7f,an integrated manner in the shaft and, if desired, can even be looped through from one rotary drive unit to the next. In this connection, it has furthermore proven to be advantageous to design the coupling elements at the axial ends of the outwardly protruding shaft as drive connections according to the tongue and groove principle. Any type of external coupling can thus be prepared by this arrangement and can therefore be carried out rapidly. In this connection, it is furthermore advantageous to extend the rotary drive unit in this modular manner by means of a torque transmitter which converts the exact rotational position of the shaft of the rotary drive unit into an electric signal, as a result of which the electric lead can be passed through the shaft in a particularly simple manner. Furthermore, as proposed according to the invention, the rotary drive unit can be extended by means of a brake module, in order, e.g. to ensure secure rotational positioning during rapid rotational movements, or even to obtain a precisely positioned gripping movement when using a gripping element. In this case, the brake can moreover remove load from the rotary drive unit, so that in the f inal position of the gripper, the gripping pressure of the gripping elements can be achieved not by the application of pressure medium in the rotary drive unit, but by fixing the brake in the brake module.

The invention will now be described by way of example and with reference to the accomp anying schematic drawings wherein:

Figure 1 shows a rotary drive,unit having a brake module and a torquetransmitter-added in a modular manner; Figure 2 is a montage of an assembly consisting of two rotary drive units and a torque"transmitter, and 1 Figure 3 shows a rotary drive unit having a gripper and a torque transmitter.

Figure 1 illustrates one embodiment of the invention, showing a rotary drive unit 1 having integrated ducts 2, 2f in the shaft 3 carrying pressure medium and electric leads. The actual rotary drive unit is designed to have a widened portion in one of the cover regions 4 and is shown there with integrated control valves 5 and the corresponding connections to the pressure-medium lines 2. The axially extending ducts 2 in the shaft are connected in a pressure-mediumproof manner in the region of the cover 4 containing the control valves 5 to the corresponding radially extending bores 6. These radially extending bores open into the grooves 7 which are arranged in an annular manner in the guide bore 8 guiding the shaf t 3 towards to the exterior. As the shaft 3 is secured against axial displacement, it is ensured that the corresponding bore 6 and thus the corresponding pressure-medium duct 7 opens in a pressuremediumproof manner into the groove provided in any operational situation. For pressure-mediumproof sealing, on the one hand, of the grooves with respect to one another and, on the other hand, of th:e grooves within' or outside the housing, the shaft 3 is:provided with'-the corresponding annular recesses 9, in which sealingirings are arranged. These sealing rings are situated in the corresponding recesses of the shaft and simultaneously press -.against the wall of the guide bore 8, so that the corresponding tight seal is produced in this manner. In this embodiment, both control valves 5 and servo valves 10 are arranged within the gover 4. The servo valves 10 are connected to a.pressure-medium supply port P leaeing towards the exterior and moreover open at sui.table points into the movable pressure chambers 14 formed by the belt 15. The control valves 5 are also connected to a pressure-medium port P leading towards the exterior.

In this embodiment, the pressure-medium ducts 2 in the shaft 3 are guided towards the exterior by an output rotary disc 16 arranged on one of the end faces of the shaft, although they can also, e.g. simply protrude from the shaft and be guided to a further rotary drive unit, which is in turn coupled to the ducts at the shaft side in such a manner that separate valves and separate pressure-medium ports can be dispensed with in this further rotary drive unit. This means that the pressureinedium ducts can be looped through in this manner from one raodule to the next. This results in very simple and compact extension of the rotary drive unit. In this embodiment, the rotary drive unit 1 is connected to a brake module 11 which is coupled to the shaf t 3 of the rotary drive unit 1 by means of coupling elements 20, 21 according to the tongue and groove principle. The shaft arranged in the brake module 11 is provided with a disc brake 12. Both the shaft of the rotary drive unit and the shaft of the brake module are provided with a through duct 21 which can be extended from one module to the next, and which, in thir;' example, is provided for the conveyance of electric leadF.. The torque transmitter 13 coupled above the brake module 11 again by the tongue and groove principle acts as a rotary potentiometer, wherein the electric leads can be passed-through the corresponding duct for signal detection, as far as the other end of the shaft, which protrudes from the entire assembly.

Figure 2 illustrateE an embodiment showing the coupling of two rotary drive units 1, 11, where'in'the other rotary drive unit 11 can be coupled to the first rotary drive unit 1 without 1 separate valves and pressure-medium ports. The supply of the rotary drive unit 11 without separate ports and valves is effected as already described in connection with Figure 1, by means of ducts leading from one module to the next. The use of two rotary drive units provides double torque that can be detected to the exterior of the shaft. This torque can be.increased by any desired multiple combination of rotary drive units. The coupling elements 20, 21 at the axial ends of the shaft 3, which are designed according to the tongue and groove principle, can be seen clearly here. It has proven to be advantageous for the coupling elements 20, 21 at the axial ends of the shaft 3 in each of the rotary drive units to be designed at one side as a conical groove and tongue arrangement and for the corresponding other axial end of the shaft to be provided with a bore having the corresponding tongue and groove contour for receiving a tongue and groove pin of this kind. A simple combined arrangement is possible in this manner.

Figure 3 shows an embodiment in which a rotary drive unit 1 for coupling to a gripper 30 is provided. The rotary drive unit requires only the coupling elements 20, 21 described hitherto in order to operate the latter. -- This means -that, in general, all of the extending -modules can be adapted to one another in such a manner that the coupling -- elements 20, 21 can always be fitted to any module.

Claims

T 1. A pressure-medium operated rotary drive unit comprising a housing for connection to a source of pressure medium and which is sealed by means of f lat covers; a rotatable shaft extending out of the housing through the cover and a belt arranged at least partly within the housing to form movable pressure chambers, and operatively connected to the shaft, wherein axially extending ducts for receiving and advancing the pressure medium to the pressure chambers, and electric leads, are arranged within the shaft, the shaft being provided at its two axial ends with coupling elements for the coupling external to the housing of mechanical and/or electric additional modules that can be coupled to the rotational movement.
2. A rotary drive unit according to Claim 1 wherein the shaft, at least in one of the cover regions, has radial bores connected to the pressure medium ducts, the guide bore in the cover guiding the shaft out of the housing having circular grooves aligned with and in f luid communication with the bores carrying the pressure medium.
3. A rotary drive unit according to Claim 3 including control valves arranged within the said cover and in f luid communication respectively with the grooves and with external ports inthe cover.
4. A rotary drive unit according to Claim 2 or Claim 3 wherein sealing rings Are disposed in a plurality of annular recesses in the shaft adjacent the grooves for sealing the junctions between the grooves and the radial bores.
5. A rotary drive 'unit according to any preceding claim including servo valves arrange-within the cover, and in fluid cc,mmunication respectively with the pressure chambers and with external ports in the cover.
6. A rotary drive unit according to any preceding Claims wherein the coupling elements are designed as drive connections according to the tongue and groove principle.

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7. A rotary drive unit according to any preceding Claim coupled with at least one further rotary drive unit.
8. A rotary drive unit according to any preceding Claim connected in a modular manner to a torque transmitter.
9. A rotary drive unit according to Claim 8 wherein one of the ducts conveys the electric leads and extends to the torque transmitter.
10. A rotary drive unit according to any preceding Claim connected to a brake module.
11. A rotary drive unit according to preceding Claim connected to a gripper module for converting the rotational movement into a centring gripping movement.
12. A pressure-medium operated rotary drive unit substantially as described herein with reference to the accompanying drawings.